It could be as simple as a break-in to smooth out the parts. Remove the magazine and with the gun empty, lube the rails and then rack the slide back and release. Do this (rack and release) a hundred or so times. Disassemble and look for shiny spots. The slide can be dragging on the frame's rails. Rails may also be bent or dented. Check the frame tunnel for drag marks too. Shiny spots indicate wearing surfaces.

Be sure to check that the link swings freely.

Also check the plunger for nicks, dents or bends.

Check the recoil strength. Compare it against a factory fresh one (length).